In a conventional laparotomy, the organ that inhibits the surgery can be manually spread, but it is known that the organ cannot be easily spread and that it is difficult to ensure a field of view optimum for the surgery under endoscopic surgery. For example, a method of injecting gas into the body cavity to ensure the field of view and the operation space is known, but such method requires full anesthesia and the invasiveness is not actually low.
To alleviate the problem of field of view, and the like and to facilitate the endoscopic treatment, an instrument called a retractor that excludes or tugs an organ to be treated or an organ that inhibits the field of view during the treatment, and the like, has been developed. As a basic function, it is desired that an instrument can be inserted through a small opening passage such as a trocar (pallium tube) or a small incision that serves as an insertion passage when inserting the retractor into the body. Therefore, the retractor needs to have a small diameter (e.g., desirably smaller than or equal to 10 mm in the case of trocar, and smaller than or equal to 20 mm in the case of small incision) and to have a rod-like form at least at the time of insertion, whereas after the insertion into the body cavity, the retractor is demanded to be deformable to a shape an excluding section has a large area of a certain degree to widely and safely exclude the target.
According to the conflicting demands described above, variously devised retractors are being proposed and are commercially available. For example, the retractor in which the excluding section opens to a fan shape has been provided (e.g., Patent Literature 1). At the time of insertion of the trocar into the abdominal cavity, a fan-shaped excluding section is folded and accommodated inside a rod-shaped tube, and is pushed out by the rod-shaped tube in the body cavity to be spread to a fan shape. A structure of opening the fan-shaped excluding section to an arbitrary size by manual operation and a structure in which an angle between the excluding section and a base section varies are known, where such structures are suited for excluding liver and intestine as the advantage thereof is that the organ can be excluded relatively widely. The shape is not limited to a fan shape, and various shapes such as a diamond shape, and the like have also been proposed.
In particular, development of a retractor that more effectively excludes the organ and that excels in operability is desired.